Travel control apparatuses for automatically performing lane change of a vehicle have been conventionally known. Such a travel control apparatus may use a known technique of determining whether or not a space for lane change exists in an adjacent lane to the lane in which the subject vehicle travels and executing the lane change when the space for lane change exists in the adjacent lane (see WO2010/082353).
In the above conventional technique, when a space for lane change does not exist in the adjacent lane, the lane change is not performed but, unfortunately, the driver cannot perceive the reason that the lane change is not performed. In particular, if lane change is not performed for the reason that a space for lane change exists in the adjacent lane at the present time but the space for lane change will disappear from the adjacent lane after a time required for lane change, uncomfortable feeling may be given to the driver who expects lane change.